1. Field of the Invention
The present invention relates to an ink jet recording apparatus, particularly, to a conveying device for the ink jet recording apparatus.
2. Description of the Related Art
There is a type using a recording head of a full-line type in an ink jet recording apparatus, which is capable of recording a high-quality image at a high speed. In this recording apparatus, a method has generally been known in which an electro-static force is generated in a conveyor belt by applying electric charge thereto from electro-conductive electrodes provided in the conveyor belt to attract a conveyed article.
The above-mentioned conveyor device will be described with reference to FIGS. 1 to 3.
As shown in FIG. 1, the conveyor belt is formed of electrode plates 36a, 36b made of electro-conductive metal, a base layer 36c, a surface layer 36d and charged members. The charged members and the surface layer 36d are made flat and function as insulation layers for insulating the electro-conductive members from outside.
FIG. 2 is an illustration of a conventional apparatus as seen in the lateral direction, and FIG. 3 is a top view thereof.
In FIG. 2, charging means includes a brush 51′, an electrode 52′ and a support member 53′.
The charging brush 51′ is brought into contact with the charged members 36e for the purpose of supplying electric charge to the latter. The electric charge is supplied from the charging brush to the electrode plates 36a to generate an electro-static force.
The charging means are arranged both on left and right sides to be capable of supplying voltages different from each other; for example, one supplies a plus voltage and the other supplies a minus voltage. Thereby, it is possible to always generate a favorable attracting force.
Also, ink jet recording heads 7K, 7C, 7M and 7Y are arranged above the conveyor belt closer thereto so that an image is formed when a copy is conveyed.
According to such a structure, it is necessary to approach the ink jet recording heads as close as possible to the conveyor belt so that the hitting accuracy of ink dots ejected from the recording heads is improved to obtain a favorable image free from the printing unevenness.
On the other hand, the ink head recording head is not always constituted by materials resistant to a high voltage but may generally be often weak to the static electricity or a high voltage. Thus, since the high voltage is always applied to the conveyor belt, there may be a leakage current between the electro-conductive section of the conveyor belt and the ink jet recording head if the insulation layer of the conveyer belt is damaged during the use due to a wear or a fatigue, resulting in the malfunction of the recording head.
Further, when the conveyor belt having a defect such as a pin hole is continuously used as it is, the damage of the recording head becomes larger to cause the trouble in the printed image.